scholarly journals Second-order Solutions for Steady Magnetohydrodynamic Channel Flow with Anisotropic Conductivity

1972 ◽  
Vol 25 (6) ◽  
pp. 719
Author(s):  
DM Panton
Keyword(s):  
Reynolds Number ◽  
Perturbation Expansion ◽  
Magnetic Reynolds Number ◽  
Arbitrary Cross Section ◽  
Second Order ◽  
Anisotropic Conductivity ◽  
Square Channel ◽  
Flow Parameters ◽  
Flow Through ◽  
Magnetohydrodynamic Channel

Further investigation of steady magnetohydrodynamic flow through a straight channel of arbitrary cross section with nonconducting walls is considered, in the presence of anisotropic conductivity due to the Hall effect, where no restriction is made on the Reynolds number or magnetic Reynolds number. An approximate solution is provided by a perturbation expansion in terms of the Hall parameter, assumed small. Corrections are made to the first-order solutions established by Panton and Hosking (1971) and the solutions are then extended to the second order for a square channel. It is found that both the Reynolds number and magnetic Reynolds number terms have a significant influence on the mass transport, the former far outweighing the contribution to the flow established by Tani (1962) for the values of the flow parameters assumed.

scholarly journals Theoretical Study of Compressible Flow through Aneurysms

2021 ◽  
Author(s):  
Maria Jumani
Keyword(s):  
Reynolds Number ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Pressure Gradient ◽  
Theoretical Study ◽  
Reynolds Numbers ◽  
Centerline Velocity ◽  
Flow Parameters ◽  
Flow Through ◽  
Wall Shear

The goal of this research is to analyze the effect of blood flow through expansions by using the KarmanPohlhausen method. The Karman-Pohlhausen method has previously been used in several research works to analyze the flow through constrictions. In this Thesis, the effect of different flow parameters (Reynolds number, compressibility, and slip) on pressure, pressure gradient, centerline velocity, and on wall shear stress are analyzed. Our results show that the pressure gradient curves are most affected by increasing Reynolds number and compressibility, as well as for smaller slip values (ws0). Furthermore, the scaled centerline velocity was least affected by varying Reynolds and Mach numbers, whereas changes are observed in centerline velocity curves for different slip values. The wall shear stress was essentially unchanged by the Reynolds numbers, compressibility range and slip values considered in this Thesis.

The Influence of the Wall on Flow Through Pipes Packed With Spheres

1990 ◽  
Vol 112 (1) ◽  
pp. 84-88 ◽  
Author(s):  
R. M. Fand ◽  
R. Thinakaran
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Porous Media ◽  
Turbulent Flow ◽  
Porous Matrix ◽  
Circular Cylinders ◽  
Empirical Equations ◽  
Flow Parameters ◽  
Flow Through ◽  
Dimension Ratio

This paper presents the results of an experimental investigation that is a sequel to a previously published study of the flow of fluids through porous media whose matrices are composed of randomly packed spheres. The objective of the previous study was to accurately determine the ranges of the Reynolds number for which Darcy, Forchheimer and turbulent flow occur, and also the values of the controlling flow parameters—namely, the Kozeny-Carman constant for Darcy flow and the Ergun constants for Forchheimer and turbulent flow—for porous beds that are infinite in extent; that is, practically speaking, for sufficiently large values of the dimension ratio, D/d, where D is a measure of the extent of the bed and d is the diameter of a single spherical particle of which the porous matrix is composed. The porous media studied in the previous and present experiments were confined within circular cylinders (pipes), for which the dimension D is taken to be the diameter of the confining cylinder. The previous study showed that the flow parameters are substantially independent of the dimension ration for D/d ≥ 40. For D/d < 40, the so-called “wall effect” becomes significant, and the flow parameters become functionally dependent upon this ratio. The present paper presents simple empirical equations that express the porosity and the flow parameters as functions of D/d for 1.4 ≤ D/d < 40. Transitions from one type to another were found to be independent of D/d and occur at values of the Reynolds number identical to those reported in the previous study.

scholarly journals Theoretical Study of Compressible Flow through Aneurysms

2021 ◽  
Author(s):  
Maria Jumani
Keyword(s):  
Reynolds Number ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Pressure Gradient ◽  
Theoretical Study ◽  
Reynolds Numbers ◽  
Centerline Velocity ◽  
Flow Parameters ◽  
Flow Through ◽  
Wall Shear

The goal of this research is to analyze the effect of blood flow through expansions by using the KarmanPohlhausen method. The Karman-Pohlhausen method has previously been used in several research works to analyze the flow through constrictions. In this Thesis, the effect of different flow parameters (Reynolds number, compressibility, and slip) on pressure, pressure gradient, centerline velocity, and on wall shear stress are analyzed. Our results show that the pressure gradient curves are most affected by increasing Reynolds number and compressibility, as well as for smaller slip values (ws0). Furthermore, the scaled centerline velocity was least affected by varying Reynolds and Mach numbers, whereas changes are observed in centerline velocity curves for different slip values. The wall shear stress was essentially unchanged by the Reynolds numbers, compressibility range and slip values considered in this Thesis.

Dissipation and Cavitation Characteristics of Single-Hole Orifices

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Stefano Malavasi ◽  
Gianandrea Vittorio Messa
Keyword(s):  
Reynolds Number ◽  
Pressure Coefficient ◽  
Diameter Ratio ◽  
Incoming Flow ◽  
Relative Thickness ◽  
Self Similarity ◽  
Pressure Losses ◽  
Geometrical Characteristics ◽  
Flow Parameters ◽  
Flow Through

The purpose of this work is to study the dependence of the pressure losses through sharp-edged orifices with respect to the most significant parameters and to find an efficient way to check whether cavitation is likely to occur. Computational fluid dynamics was used to simulate the flow through orifices with different geometrical characteristics for various incoming flow velocities. In particular, the diameter ratio was varied between 0.39 and 0.70, the relative thickness between 0.30 and 1.40, and the pipe Reynolds number between 3.85 × 104 and 1.54 × 105. The computed pressure drop coefficient in the region of self-similarity with respect to the pipe Reynolds number was first compared to that obtained from some literature models. Afterwards, the comparison with experimental data revealed that an extended pressure criterion is suitable to predict the presence of cavitating conditions. A dimensionless minimum pressure coefficient was then defined, and its dependence upon the above mentioned geometrical and flow parameters was investigated. Finally, a practical formula for the prediction of cavitation was provided.

Correlations for the discharge coefficient of rotating orifices based on the incidence angle

2005 ◽  
Vol 219 (5) ◽  
pp. 333-352 ◽  
Author(s):  
A Idris ◽  
K. R. Pullen
Keyword(s):  
Fluid Dynamics ◽  
Reynolds Number ◽  
Discharge Coefficient ◽  
Incidence Angle ◽  
Pressure Ratio ◽  
Cross Flow ◽  
Flow Parameters ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Good Agreement

The flow through rotating orifices is of interest to the designer of machines incorporating such features. The designer often requires a set of correlations which can be used to check out preliminary designs and converge on a solution prior to attempting detailed and expansive analysis. The correlations given in this paper are based on the incidence angle, i, of the flow into the orifice and they allow the discharge coefficient for rotating orifices to be estimated for as many conditions and geometries as possible. The approach adopted is to group the parameters that affect the discharge coefficient to i = 0° (Reynolds number, orifice chamfer and radius, L/d ratio, pressure ratio, and pumping effect) and i ≠ 0° (rotation of the disc, preswirl, cross-flow, and the angle of inclination of the orifice). The effect of each parameter on the discharge coefficient can easily be observed when using this method. Furthermore, the method can predict the discharge coefficient for systems that have various parameters that are combined together. There is a good agreement between the correlations and the experimental results and the available data on rotating orifices in the open literature. The correlations also agree with various combinations run in computational fluid dynamics (CFD). The approach adopted in this paper, which is based on the incidence angle, can assist designers to find the combination of geometric and flow parameters that gives the best discharge coefficient for rotating orifices.

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